It is already enabled (bzr trunk), I just didn't see it. Strangely
enough, using `lexical-let' inside a lexical binding enabled file
produces tons of "bad lexing" errors when used with named functions
(It doesn't in lexica-binding disabled files).

I don't know what "used with named functions" mean.
Stefan

In the context of what was talked about
(lambda () (message "foo"))
would be an unnamed function, whereas
(defun foo () (message "foo"))
would be a function named "foo"